40. High Availability Databases Explained | Replication vs Failover

Описание: Database replication is one of the most important building blocks of scalable and highly available systems.

In this video, we explain database replication from scratch, focusing on real-world system design decisions used by companies like Netflix, Instagram, Facebook, and Amazon.

You’ll learn how replication improves availability, performance, and fault tolerance — and what trade-offs engineers must handle in production systems.

What you’ll learn in this video:

What database replication really is

Why replication is critical for high availability

Leader-follower (primary-replica) replication explained

How read and write splitting works

What read replicas are and how they scale systems

Replication lag and why it happens

How replication affects consistency

Failover challenges and split-brain problems

Real-world use cases in e-commerce, social media, and analytics

Replication strategies in MySQL, PostgreSQL, MongoDB, Cassandra

Best practices for production-ready replication

Trade-offs between availability, performance, and consistency

Who should watch this video:

Backend developers and software engineers

System design interview candidates

SDE-1, SDE-2, and SDE-3 engineers

Developers working with distributed systems

Anyone building scalable backend architectures

Replication is not optional at scale — understanding it properly will help you design robust, production-grade systems.

#DatabaseReplication
#SystemDesign
#BackendEngineering
#DistributedSystems
#Databases
#HighAvailability
#ReadReplicas
#SoftwareArchitecture
#ScalableSystems
#SystemDesignInterview